The initiative unites a group of specialists from around the nation to validate technology that can assist in the search for life beyond our solar system

The inaugural space mission led by the University of Michigan’s Department of Astronomy is set to be launched in 2029, backed by a NASA grant amounting to $10 million.

This mission is named STARI—STarlight Acquisition and Reflection toward Interferometry—and it aims to showcase the practicality of an innovative method for examining exoplanets, or planets that exist beyond our solar system.

This method could potentially be employed in the future to gain deeper insights into whether any of the known exoplanets might sustain life as we understand it.

“We have identified thousands of these planets, predominantly using indirect methods—in other words, not directly through the light they emit,” remarked John Monnier, a professor of astronomy at U-M and the project leader. “It’s time to alter that.”

The funding was provided by the Astrophysics Research and Analysis program from NASA’s Astrophysics Division.

Demonstration of technology

STARI itself is not intended to reveal new information about those planets. Instead, it will illustrate a vital technology for a powerful method known as interferometry to substantiate that larger, pricier upcoming missions can leverage this strategy to seek signs of life on other planets.

Interferometry necessitates several satellites, spaced hundreds of yards apart, performing in exact synchronization to bounce starlight among them. The satellites must transmit light to one another with precision while moving and being positioned approximately the length of a football field apart.

This degree of control and stability is what STARI aims to demonstrate using two compact satellites referred to as CubeSats. Both satellites in the STARI mission—named STARI-1 and STARI-2—are approximately the size of a briefcase.

“The most challenging aspect of the STARI mission will be attaining the precise synchronization and control necessary for formation flying on a CubeSat platform,” stated Gautam Vasisht, a project collaborator and research scientist at NASA’s Jet Propulsion Laboratory, or JPL.

The benefit of utilizing CubeSats is that they require only a fraction of what it would need to launch a larger mission. While they cannot fully replicate the capabilities of larger, more advanced satellites, CubeSats provide a cost-effective means to verify components of the technology essential for those larger missions.

“By experimenting with formation flying technologies on a CubeSat framework, STARI paves the road for future missions that could transform our capacity to investigate remote Earth-like planets,” Gautam explained. “It demonstrates how inventive engineering and robust collaboration can extend the limits of what is achievable in astronomy.”

Alongside Vasisht from JPL, the collective includes specialists from various parts of the country, led by Simone D’Amico at Stanford University, E. Glenn Lightsey at the Georgia Institute of Technology, and Leonid Pogorelyuk at Rensselaer Polytechnic Institute, or RPI.

James Cutler, a professor of aerospace engineering who is also at the helm of the CubeSats Working Group in the U-M Space Institute, is additionally a co-investigator.

An all-STARI team

Collaboration is an essential and purposeful element of the initiative.

“The group merges essential required proficiency and experience in various significant domains, such as formation-flying, optical interferometry, propulsion, and system engineering,” stated D’Amico, an associate professor in aeronautics and astronautics who heads the Space Rendezvous Laboratory at the Stanford School of Engineering.

D’Amico, for example, has contributed to the design and operation of multiple past small satellite formation-flying missions, particularly focusing on their guidance, navigation, and control systems. He and his team possess expertise in several crucial areas that STARI will uniquely integrate with an exceptionally high degree of precision.

“This has never been achieved before,” D’Amico noted. “Therefore, the STARI technology demonstration holds immense intrinsic value, not merely as a precursor to landmark missions for larger interferometers.”

Lightsey, a partner and professor at Georgia Tech, considers STARI as part of a broader transformation occurring in space endeavors.

Instead of consolidating all the technology a mission requires within a single spacecraft, missions are striving to achieve more than was once feasible by distributing the responsibilities across multiple vehicles and even terrestrial instruments.

“I believe this is a significantly more potent concept,” remarked Lightsey, a seasoned participant in numerous small satellite missions whose team is responsible for STARI’s maneuvering system.

“It’s poised to yield remarkable scientific breakthroughs and enhancements in human existence on Earth due to the capabilities it offers,” he expressed. “I’m thrilled to be part of a noteworthy project like this that could genuinely advance the current standards.”

While this is the inaugural mission led by Michigan’s astronomy department, the University of Michigan has a long-standing history of involvement in space exploration. In fact, Cutler directs the Michigan Exploration Laboratory, or MXL, which has previously launched nine satellites.

“We have pioneered the usage of CubeSats for studying space weather and exploring missions near Earth, beyond Mars, and to the moon,” Cutler stated. “We’re eager to assist astronomers in reaching even farther with STARI.”

MXL will coordinate and enhance the STARI satellites.

“Although many of our faculty have held prominent roles in prior NASA astrophysics missions, having STARI spearheaded by U-M Astronomy represents a significant milestone,” said Michael Meyer, chair of the Department of Astronomy. “We anticipate a bright future, collaborating with partners like the University of Michigan Space Institute.”

STARI, STARI flight

Researchers have already demonstrated the capability to derive insights about the makeup of an exoplanet’s atmosphere by examining the light that traverses it, a technique known as transmission spectroscopy.

However, astronomers are striving to create improved instruments specifically designed to detect the infrared light emitted by cooler planets against the brilliance of their much more luminous and hotter host stars. This would allow scientists to analyze the light from the planets for indications of life as we understand it.

One method researchers are employing is constructing progressively larger telescopes on Earth to gather as much light as possible. This is the objective of the Extremely Large Telescope, currently under construction by the European Southern Observatory in Chile. With a 128-foot diameter primary mirror, it will become the world’s largest telescope for capturing visible and near- to mid-infrared light upon its completion in 2028.

U-M astronomers are assisting in developing the initial instruments for the Extremely Large Telescope, but they are also interested in the supplementary approach of interferometry.

This method would involve multiple satellites observing light from a distant source and reflecting it to another spacecraft that combines the beams. In this scenario, the reflected light overlaps, generating interference patterns that help eliminate starlight and uncover clues about an exoplanet’s atmosphere.

Increasing the distance between the satellites enhances the resolution of the technique, yet also raises the complexity, according to Pogorelyuk, an assistant professor and collaborator at RPI.

Although STARI will not be conducting interferometry, it will be evaluating its satellites’ capacity to gather light into a hair-thin optical fiber and transmit light to its counterpart, positioned up to 100 meters away.

The satellites must sustain their position and orientation in relation to one another within millimeters—approximately the thickness of a dime—while maneuvering around in a low-Earth orbit.

“The method of operation in space differs significantly from that on Earth. Nothing is anchored to the ground—everything is in motion as if gliding on ice and cannot come to a halt,” Pogorelyuk remarked. “From an engineering viewpoint, it’s a fascinating challenge.”

The team is enthusiastic about addressing the challenges and enhancing prospects for future endeavors like the Large Interferometer For Exoplanets, or LIFE, led by the Swiss university ETH Zürich. LIFE is proposed as a component of the European Space Agency’s long-term scientific planning, referred to as Voyage 2050.

“While we believe the global scientific community strongly endorses our aspirations, we also recognize that we still have some scientific and technological obstacles to overcome before we can have LIFE ready for launch,” stated Sascha Quanz, the lead investigator for LIFE and professor at ETH Zürich.

“Initiatives like STARI are exemplary instances of how more compact, swifter missions with a distinct focus can aid in the development and trial of pertinent technologies for LIFE in a highly efficient manner.”

LIFE would utilize larger satellites and a greater number of them to examine distant atmospheres for signs of life, but STARI’s compact CubeSats could significantly demonstrate that such a mission is feasible, as Monnier suggested.

“We aspire for the technology evolved from STARI to pave the way for a future space interferometer capable of imaging Earth-like planets orbiting nearby stars, with sufficient capability to detect life signals,” he concluded.